Abstract
Objectives: To compare relative measures of disparity in rates of favorable events with those in rates of adverse events.
Methods: Relative measures of disparity are applied to four health indicators to demonstrate how the size of a disparity between groups, and changes in disparity over time, depend on whether indicators are expressed in terms of favorable or adverse events.
Results: The size of an absolute measure of disparity is the same whether favorable or adverse events are studied. The size of a relative measure of disparity depends on the rate for each group and the reference point from which the disparity is measured. The rates for each group and for the reference point depend on whether the indicator is expressed in terms of favorable or adverse events. Relative measures of disparity, and conclusions about changes in relative measures of disparity, depend on whether indicators are expressed in terms of favorable or adverse events.
Conclusions: When relative measures of disparity are used to monitor changes in disparity over time or to compare disparities across different indicators, disparities should be measured in terms of adverse events.